As a southern from the New Orleans area, ya'll is as natural a part of everyday language as it comes, and generally when it is heard by people who aren't from the south it comes off as smug, or cringe. Generally because they put a strong emphasis on the world, when it is rarely warranted.

It's like when people try to pronounce "New Orleans" as "nawlins" (to be clear, no one native says it this way, its tourist trap t-shirts that pronounce it this way), or some other such silly thing. Conversely there are many words that are said in unique ways in the region and part of being accepted as a transplant is people who learn to say those words with the regional dialect.

It may come as a shock, but I doubt anyone in the south (outside of the irish channel) really gives the New York Times opinion on southern language much of a second thought.